The northern border region of Sonora is almost entirely remote country. Historically it has been used by Mexicans and Tohono O'odham primarily as relatively unprofitable ranch land. This area has amazing economic potential, however, solely because the U.S./Mexican border crosses it. Locals as well as folks from far away take advantage of the illegal drug trade and migrant smuggling industries that have proliferated with increased law enforcement and demand from U.S. drug consumers.
For decades these activities were primarily carried out in urban areas (and to some degree still are), but in the last couple of decades the U.S. Border Patrol has systematically worked to push these activities into more remote and wild parts of the borderlands, ignorantly thinking it would help them gain the upper hand. The majority of drugs still come through the ports of entry, but many migrants are being pushed into attempting more remote and dangerous crossings routes. Hundreds of migrants a year die crossing the Sonora border into Arizona, most of cold or dehydration in the summer heat.
The current U.S. policy on drugs and migrants is making these economies increasingly valuable, and just like during prohibition, people are taking advantage of record profits this policy enables, forming enormous organized cartels and inviting more corruption and violence.
Activities and infrastructure from the U.S. border policy is wreaking havoc on ecosystems along the border. Border wall construction is quickly becoming one of the biggest threats to ecosystems in the Sonoran Desert and Sky Island regions that cut across Arizona and Sonora.
The border wall severs cross-border ecosystems shared by Mexico and the U.S. Large and small animals alike are prevented from migrating, young from disbursing, individuals from finding new territories. The border wall's impacts to larger animals such as Jaguars, bears, or coati are obvious, but what is not are the innumerable smaller animals that are impacted. Frogs, snakes, small mammals, and even some species of birds are prevented from moving across the landscape. Activity, lights, roads and other border related disruptions are casing serious problems for a veriety of wildlife.
This will likely become even more of an issue with global climate change and the need for species' populations to adjust and move to more suitable habitat farther north or higher in elevation. Predicting the effects on and needs of species is difficult, but the need for movement corridors of many species is a no-brainer.
Beyond the wall there are many other environmental impacts associated with border activities. New road construction, off road vehicles, erosion, high power flood-lights, and general increased activity are all taking they're toll on wildlife and plant-life in the border region.